Americans use Fahrenheit, but many climate reports exclusively use Celsius.

Americans use Fahrenheit, but many climate reports exclusively use Celsius.

Roger Kisby for The New York Times

Clear communication

The world’s top scientists released their latest report yesterday warning that the Earth is on pace for severe damage from climate change. But many Americans might have a hard time understanding the report because the analysis, like those before it, talks about temperatures exclusively in Celsius.

The U.S. is among just a few countries that still use Fahrenheit temperatures. And while Americans are a relatively small audience on a global scale, they are an important one for climate science: The U.S. has historically emitted more planet-warming A thermometer reading in Death greenhouse gases than any other country. Valley National Park

Improving Americans’ understanding of

the issue could be crucial to any push for changes.

Why does excluding Fahrenheit matter? Most Americans lack experiences from their own lives to make sense of scientists’ warnings that the Earth could warm by up to 1.5 degrees Celsius above acceptable levels. To them, it is a small, meaningless number.

By translating that figure to its Fahrenheit equivalent — 2.7 degrees — it can take on a clearer meaning. Katharine Hayhoe, a climate scientist, uses the analogy of a fever: Think about how much worse you feel when you run a fever of 101.3 degrees Fahrenheit, 2.7 degrees above normal. That fever is the equivalent of what the planet is facing.

Most Americans can grasp that analogy because it speaks to their own experiences. They can’t do that with Celsius. “It is absolutely essential to communicate in terms and language that people understand,” said Hayhoe, who is from Canada, which uses Celsius.

The exclusion of Fahrenheit in scientific reports is not the main obstacle to more action on climate change. Broader science denial and the world’s reliance on fossil fuels are much bigger barriers. But including Fahrenheit figures is a small change — a matter of plugging some numbers into a calculator — that could help drive more action.

Today’s newsletter will look at the new climate report and how close, or not, the world is to avoiding the worst consequences.

Expect more catastrophes

The new analysis, a synthesis of six previous reports by the United Nations’ climate group, presents a mixed picture of the world’s fight against climate change.

Here are three takeaways:

1) The world is on track to surpass a significant level of warming.

The world is likely to hit what scientists consider relatively safe levels of warming — 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial temperatures — by the early 2030s, the report warned. Countries could still take steps to prevent that, by slashing greenhouse gas emissions in half by 2030 and no longer adding carbon dioxide to the atmosphere by the 2050s. But the required measures are so extreme that they seem increasingly unlikely, many experts say.

2) On the current track, brace for more disasters.

Continued warming will mean more catastrophic flooding, deadly heat waves, crop-destroying droughts and other extreme weather. Some of those effects are already visible. Last year, record-breaking heat waves hit much of the world, including the U.S. and Europe, and floods submerged a third of Pakistan.

3) The world has made some real progress. In the past, climate reports warned that warming could surpass four degrees Celsius (7.2 degrees Fahrenheit) by 2100. Today, the Earth is on a trajectory of around two to three degrees Celsius (3.6 to 5.4 degrees Fahrenheit), thanks to the uptake of cleaner energy and to projections that coal use will decline. That difference of a few degrees can, like a fever, prevent more catastrophic events. And as my colleague Somini Sengupta noted, pivoting away from fossil fuels is the fastest way to stop global warming.

The bottom line

Despite some progress, the world is still on track to face devastating outcomes from climate change. To prevent the worst, scientists are calling for a massive effort that will require the world’s most powerful and richest countries to work together.

Getting so much of the world onboard requires communicating the problem in a way everyone can understand. Excluding the temperature measure used by the U.S. and some other nations hinders that mission. Offering different versions of reports with Celsius and Fahrenheit could help address that issue, or scientists and news outlets could translate Celsius-focused reports to Fahrenheit in their own work.

More on climate change

• The world will have to spend more on climate measures because it waited so long to act, the report found. The U.S. said it would reassess its spending.

• New technologies promise to take carbon out of the air, but some critics say they’re overblown. See how they work.

• Expensive pipeline projects are again starting fights, but these pipelines are different: They’re intended to help store carbon underground.

• A very wet winter has eased California’s drought. These maps and charts show the difference.

• Electric cars are becoming more affordable. One reason: cheaper lithium for batteries.

• President Biden issued his first veto to preserve investment managers’ ability to take account of climate change.